A bench press exercise is conventionally performed by a weight lifter by lying on his back along a narrow supporting bench while the weights are pressed upwards by the arms and chest muscles directly above the user's chest. The goal of a bench press exercise is to strengthen the pectoral muscles in the chest. In order to do this it is necessary to isolate the pectoral muscles during the bench press exercise so that other muscles, such as the shoulders, are not brought into play. Other exercises are designed for the shoulder muscles but the bench press is uniquely intended to strengthen the pectoral muscles in the chest region. Conventional bench press apparatus unfortunately supports the entire back of the user on the same horizontal plane and this includes support for the shoulders directly beneath the shoulder blades. When this occurs the shoulder muscles are engaged during the bench press lift and the pectoral muscles are not isolated as desired. Some weight benches such as that shown in Rogers U.S. Pat. No. 4,319,747 provide a curved supporting surface in a bench press apparatus which provides relief beneath the shoulders thus forcing the sternum upwards. The Rogers bench, however, is curved along its entire length with the attendant problem that a user could slip off to either side during the exercise. Also, the Rogers bench is a continuous curve and provides no support either for the shoulders or other parts of the body below the apex of the curve which would extend just beneath a user's spine.